In a known scanning endoscope, light emitted from an radiation end part of an optical fiber is made to scan over an object by vibrating the radiation end part, and light reflected or scattered at the object or fluorescence or the like generated in the object is detected (for example, see PTL 1).
The scanning endoscope in PTL 1 achieves a two-dimensional scanning locus of point illumination light emitted from the radiation end part by means of vibrating the radiation end part of the optical fiber at a driving frequency set according to the frequency characteristics of the optical fiber and by changing the amplitude of the vibration at a predetermined modulation frequency. Then, by storing the coordinates of respective scanning positions in the two-dimensional scanning locus of the point illumination light and the intensities of return light from the object detected when the illumination light is radiated on the respective scanning positions, an image of the object is acquired.